An overnight fire at a farmers' market in the southern Chinese city of Shenzhen killed at least 15 people and injured five, local authorities saidy.

Shenzhen's fire department said on its microblog that the fire broke out about 1.30am Wednesday (local time) at the wholesale market and engulfed an area of 1000 square meters before being brought under control by firefighting crews from 29 fire engines.

It said 15 people were dead and five injured, and that firefighters were still searching for survivors. The cause of the fire was unclear.

Authorities at the city government, emergency management office, fire department and local Communist Party offices did not immediately answer phone calls or declined to give any information.